2006ApJ...641L.133M

Despite the observational effort carried out in the last few decades, no perfect solar twin has been found to date. An important milestone was achieved a decade ago by Porto de Mello & da Silva, who showed that 18 Sco is almost a solar twin. In the present work, we use extremely high resolution (R=10⁵), high signal-to-noise ratio Keck HIRES spectra to carry out a differential analysis of 16 solar-twin candidates. We show that HD 98618 is the second-closest solar twin and that the fundamental parameters of both HD 98618 and 18 Sco are very similar (within a few percent) to the host star of our solar system, including the likelihood of hosting a terrestrial planet within their habitable zones. We suggest that these stars should be given top priority in exoplanet and SETI surveys.